Apparatus for splicing rubber articles



Feb. 17, 1942.

5 sh'eets-sheet 1 Filed Feb. 4, 1939 grim] L/eromeF/Bhy/e/h Feb. J. F.CAMPBELL ETAL 2,273,463

APPARATUS FOR SPLICING RUBBER ARTICLES Filed Feb. 4, 1959 5 Sheets-Sheet2 Feb. 17, 1942. -J. F. CAMPBELL ETAL 2,273,463

APPARATUS FOR SPLICING RUBBER ARTICLES Filed Feb. 4, 1939 5 Sheets-Sheet4 V REGULAT/NG (621* mm:

HLM 17/02 ial Gummy,

Feb. 17, 1942. J. F. CAMPBELL ETAL 6 APPARATUS FOR SFLI CING RUBBERARTICLES Filed Feb. 4, 1959 5 SheetS-Sheet'S TEMPE RR 7' URL CDNTEOL UNIT 159 JUN: TlO/V ay/a Patented Feb. 17, 1942 APPARATUS FOR. SPLICINGRUBBER ARTICLES John F. Campbell, Cuyahoga Falls, and Jerome F.Ringlein, Akron, Ohio, assignora to Wingfoot Corporation, Wilmington,Del., a corporation of Delaware Application February 4, 1939, Serial No.254,722

9 Claims.

This invention relates to improvements in apparatus for splicing rubberarticles, and it refers more particularly to such apparatus for use inJoining ends of unvulcanized inner tube and PatentNo. 2,024,577;2,024,578; and 2,040,466.

While those methods and machines have been extensively used with greatcommercial success, they are improved by the present invention. Inpracticing the inventions of the above-enumerated patents, two ends ofthe inner tube stock or the tread stock, as the case may be, are clampedflat in a pair of alined clamping devices, and while so held, said endsare cut off transversely and heated. Thereafter the freshly cut ends arebrought forcibly together and Joined preparatory to vulcanization. Thecutting has been done with heated knives traveling in a straight line,the heat from the knives enhancing the tackiness of the stock to insurea good union. Instead of effecting a transversely straight out as in theprior art, the present invention contemplates substantially oblique cutsor off-set cuts, so that when the out ends are brought together theywill first contact at one edge, and continued pressure will result inprogressive contact without entrapping any air between the Joinedsurfaces. Preferably sufllcient pressure is exerted to form fins ofexcess material around the joint, thus giving greater strength thereto.

One of the objects of the invention is to provide novel apparatus forsplicing the ends of rubber stock. I p

More specifically the invention contemplates completely flattening andholding fiat the ends of the tube stock or tread stock to be spliced andcutting portions from the ends so held, the line of out being generallyoblique with reference to the plane of the material. In one form of theinvention the material is held flat in a pair of clamps which aremovable toward and from each other and. by moving said clamps slightlyaway from each other during the cutting operation. the line of the cutis changed. In one respect this effects a combined cutting and tearingaction on the rubber and it provides a certain amount of excess materialfor the splice. as will hereinafter be better appreciated. The cuttingmay be done with knives which preferably are heated to a predeterminedtemperature and. by changing the line of cut during the cuttingoperation. these heated knives are less likely to sear the rubber andtherefore they leave the freshly cut ends of the rubber in bettercondition for splicing. After the cutting operation has been completedthe clamps are moved toward each other in such a way as to force thefreshly cut ends of rubber into progressive mutual contact forming aperfect splice without any air being trapped between the joinedsurfaces. which theends of the rubber are brought together is sufficientto leave slight fins of excess material surrounding the splice, thisexcess material further contributing to the perfection of the joint.

The foregoing and other objects, features and advantages of theinvention will be fully appreciated from the followingdescription inconnection with the accompanying drawings, wherein the method has beenillustrated diagrammatically and one form of apparatus has been shownfor practicing the method. In the drawings:

Figure 1 is a front elevation of the improved splicing machine with theparts shown in their respective positions at the beginning of the cycleof operations.

Fig. 2 is a fragmentary view on a larger scale partly in section andpartly in elevation, the view being taken approximately on line 22 ofFig. 1.

Fig. 3 is a complete elevation of one side of the machine with theclamping means in clamping position but without showing any stock beingoperated upon.

Fig. 4 is a rear view thereof.

Figs. 5-11 inclusive are fragmentary diagrammatic views similar to eachother but illustrating successive steps in the novel method of splicing.

Fig. 12 is a diagrammatic view of the various fluid pressure cylindersand controlling means therefor, and

Fig. 13 is a wiring diagram of the electrical connections for themachine.

Referring first to Figs. 5 to 11 inclusive, the method will be describedand it is to be understood that various forms of apparatus may beemployed for practicing such method. In the between the clamping membersl5 and I1 and directly below the protruding ends of the rubber tubestock. Cutting means such as a pair of knives 20 are moved downwardlytoward the anvil IS with their sharp ends entering the upper Thepressure with flattened wall of the tube stock. After the knives 20 havepenetrated the tube stock a predetermined distance substantiallyequivalent to that shown in Fig. 5, their downward movement isinterrupted and, while so interrupted, the clamping members l5 and I1and their associated parts are moved away from each other a very slightdistance. To a certain extent this action either tears or distorts therubber as illustrated in Fig. 6. Thereafter the downward movement of theknives 22 continues entirely through the rubber as shown in Fig. 7, thusremoving from the extremities of the tube stock small portions 2| whichare not needed and exposing freshly cut surfaces 22 and 23 which aresubsequently to be joined. After the cuts are thus completed theclamping members move farther apart so as to completely disengage therubber from the knives as shown in Fig. 8 and thereafter the knives 20return upward while the anvil l9 moves downward. It is to be noted thatthe freshly cut surfaces 22 and 23 of the rubber stock are substantiallyoblique with reference to the flattened plane of the tube stock, andthis is important in effecting a perfect splice. While the tube stock isstill held in flattened condition, the end surfaces 22 and 23 arebrought forcibly together as shown in Fig. 10. Due to the obliquity ofthe end surfaces contact will first be made adjacent the lower edges ofthe stock and thereafter continued force or pressure will bring thesurfaces 22 and 23 progressively into mutual engagement 1 in such a wayas to prevent entrapping of air between such surfaces. Preferably theends of the tube stock are pressed together sufflciently to form fins 24of excess material surrounding the joint as shown in Fig. 11. The endsof the tube stock thus pressed together become perfectly united byreason of their tacky condition and they remain so united in subsequenthandling, and they become completely merged in vulcanization.Incidentally when the tubes so spliced are vulcanized in a confiningmold, as is customary, the fins 24 of excess material substantiallydisappear by reason of the flow of heated rubber inwardly from the moldsurface, some of such excess rubber distributing itself in the wall ofthe tube and some remaining to form a slight bulging portion on theinterior of the tube and surrounding the splice.

Experience has shown that splices made by this method are superior tothose of the prior patents previously referred to and that they caneasily be carried out in large production schedules with a minimumnumber of defects. to be noticed that when the ends are severed by acombined cutting and tearing action, as illustrated in Figs. 5, 6 and 7,the first-cut portions of the surfaces 22 and 23 are quickly moved awayfrom the knives and thus they are not so likely to become seared aswould otherwise be the case when the knives are heated. The nature ofthe rubber is such that the line of out can easily be changed, as hasbeen described but obviously the method may also be practiced by movingthe knives in oblique paths rather than perpendicular to the clampedrubber stock.

When splicing inner-tube stock the interior of the tube stock is quiteheavily dusted with soapstone or other material to prevent the rubberwalls from adhering to each other and when this method is used with theoffset cut above described it is preferable to make the offset beforethe knives have gone entirely through the first wall of rubber. Thus, asthey pass through the It is layer of soapstone between the superimposedfaces of rubber, the knives will not disturb-the soapstone sumciently tointerfere with the tackiness of the end below said layer of soapstone.It is of course to be understood that, while the method has beenillustrated and described particularly in reference to splicinginner-tube stock, it is equally adaptable and effective for splicingother rubber material, such as tread bands for use in manufacturingpneumatic tires.

One form of apparatus for practicing the above-described method isillustrated in Figs. 14 inclusiveysuch apparatus including the principalfeatures of the above identified patents, to-

gether with certain additional features which are of the essence of thepresent invention. In these views of the drawings it will be seen thatthe lower clamping members l5 and II are respectively arranged upon apair of alined carriages 30 and 3| which are mounted for movementendwise toward and from each other on dovetailed guides 32 and 33. Theupper clamping members l6 and I8 are also arranged upon the carriages 30and 3| so as to be bodily movable therewith but they are pivoted as at34 to facilitate their movement into and. out of clamping positions.Preferably the clamping members I6 and I8 comprise a multiplicity ofyieldably mounted metal plates which at least partly encircle aninflatable core or airbag, the construction being substantially the sameas that described and claimed in the Christy Patent 2,040,466. Clamps ofthis type are quite flexible and thus they conform readily to thecontour of the particular material whichis being operated upon in themachine. Lever arms 35 and 36 extend rearwardly from the upper clampingmembers l6 and I8 for swinging movement about the pivotal connection 34,whereby to actuate said clamping members. The rearward ends of saidlever arms 35 and 36 are respectively connected pressure cylinders havetheir upper ends pivoted to rock or swing about the pivotal connection34 I to raise and lower the upper clamping members I6 and I8. In orderto actuate the carriages 30 and 3| for movement toward and from eachother there are provided a pair of rack bars 48 and 49 which may beattached to or integral with.

the lower portions of the carriages. These rack bars are constantly inmesh with pinions 50 and 5| which are mounted for rotation with and bygears 52 and 53, said gears being mounted at the rearward side of themachine and being constantly in mesh with a double-face rack bar 54disposed between them. The rack bar 54 is movable upwardly anddownwardly by reason of its connection with a piston rod 55 whichextends into a pressure cylinder 56 and wherein there is a pistonattached to the end of said piston rod 55. As pressure fluid is admittedalternately toopposite ends of the cylinder 56, the double-face rack bar54 is caused to move longitudinally, rotating the gears 52 and 53 andthe pinions 50 and 5 I, and as the pinions thus rotate the carriages 30and 3| and their associated parts are caused to move either toward oraway from each other dependent upon which end of the cylinder 58 has thepressure in it.

The anvil l9 (best shown in Fig. 1) comprises a relatively fiat metallicblock or plate which is movable upwardly and downwardly into and out ofthe path of relative movement of the clamping members l5, and I1. Whenthe anvil is in its uppermost position it is disposed between the endsof the clamping members I5 and I! and directly below the protruding endsof the stock clamped therein, and it is so proportioned as to givesupport to the clamped ends of the stock when said stock is beingoperated upon by the knives 28. The anvil I8 is mounted upon the upperend of a piston rod 59, the lower end of which extends into a pressurecylinder 88 wherein there is a reciprocating piston of any ordinary orpreferred form. As pressure fluid is admitted to the lower end of saidcylinder 88 the anvil is raised and as such pressure is released fromthe lower end of the cylinder the anvil is moved downwardly out of thepath of the lower clamping members and carriages.

The knives 28 having sharpened lower cutting edges are mounted above theclamping members upon a slide 62, which slide is guided for verticalmovement in an upward extension 63 of the machine frame. This extension83, as well as the parts previously described, are supported upon asuitable frame or base 64 of any preferred form. The slide 82 isappropriately secured to the lower end of a piston rod 85 which extendsinto a pressure cylinder 88 wherein there is another reciprocatingpiston for actuating the piston rod. The pressure cylinder 88 is fixedto the frame extension 83 substantially in the vertical center line ofthe machine and below another pressure cylinder 81 which is supportedupon a fixed cross bar 88 adjacent the top of the frame. Within thecylinder 81 there is a piston attached to anupwardly projecting pistonrod 89 which is disposed in the path of movement of an adjustableabutment 48 which also has associated with it an extension 1| adapted atcertain times to strike against and to actuate a normally open microswitch 12. The abutment I8 and the extension II are carried on a cross.arm I3 secured to the upper end of a pair of sliding rods 14 which aresuitably guided in the upper portion of the frame and secured to theslide 82.

When the cutting knives 28 are in their uppermost position (inactive)the abutment I8 and its associated parts are also in their uppermostpositions and thus held by fluid pressure in the lower end of cylinder88. At the same time fluid under pressure is present in the lower end ofcylinder 81. When it is desired to lower the knives for the cuttingoperation pressure is released from the lower end of cylinder 86 andadmitted to the upper end of said cylinder, thus causing the slide 62and its associated parts, including the rods "to move downwardly towardthe anvil I9. In the course of such movement the, abutment 18 will comeinto contact with the projecting end of the piston rod 89 and this willtemporarily stop the descent of the knives. At substantially the sametime the extension 1| will contact the micro switch 12, closing anelectric circuit therethrough to energize a solenoid I5 which controls anormally open three-way valve 16. As the valve I8 is thus actuated thepressure fluid is slowly released from the lower end of cylinder 81through a suitable conduit 11 and regulating check valve 18. As thisoccurs the slide 82 and its associated parts is free to move downwardlyagain under the pressure existing in the upper end of cylinder 88 untilthe knives lower end 83 of the piston rod 82 is adapted for abutmentwith the upper end 84 of the rack bar 54. Similarly the upper end 85 ofthe piston rod 82 is adapted for abutment at certain times with thelower end 88 of a piston rod 81 which extends into the cylinder 8| forconnection with a piston therein. Under certain conditions the endportions 85 and 88 are out of contact with each other but in otherconditions theyare in mutual contact for simultaneous operation duringpart of the cycle of the machine. The function of the cylinders 88 and8| and their asso-. ciated parts is to cooperate with the cylinder 58 incontrolling movement of the carriages 38 and 3| and it is to be notedthat the diameters of said cylinders 88 and 8| are greater than that ofthe cylinder 58, whereby to overpower the latter during part of thecycle.

When the machine is at rest, that is ready to commence its cycle ofoperations, the clamping members I8 and I8 are raised as shown in Fig. 2and the piston within the cylinder 58 is near the upper end of thecylinder but not up to its limit of movement. At the same time themembers 83 and 84 are in contact with each other'and the members 85 and88 are out of contact, and the pistons which control said respectivemembers are substantially in the lower ends of the cylinders 88 and 8|.At this same time the air bags 98 and 9| within the clamping members l8and I8 are deflated.

Pressure fluid, such as compressed air, is ad- 'mitted to and releasedfrom the opposite ends of the various cylinders automatically by acontrol unit 95. (See Figs. 3, 4 and 12.) This control unit-maypreferably be mounted in the base 84 of the machine and comprises asuitable casing which encloses an electric motor 98 which, throughsuitable gearing 91, drives a cam shaft 98. A plurality of cams |8|,I82, I83, I84 and I85 are secured to the cam shaft 98 for rotationtherewith and they are adapted to have their peripheries engage againsta corresponding number of cam followers desi nated generally by thereference character I88. These cam followers I88 may be of any ordinaryor preferred forms and preferably they are all similar to each other andare mounted for actuation of plungers or rods I81 which extend throughthe upper wall of the casing and extend thereinto from a'multiplicity ofvalves III, 2, H3, H4 and H5. The valves just referred to may be of thetype known commercially as Quick-as-Wink". and are char acterized byindividual casings within which I plunger rods are operable to open andclose conand downwardly at suitable times predetermined in the designingof the cams and thus operate the valves III-I I5, inclusive.

In order to simplify the machine drawings Figs. 1-4, inclusive, thepiping and valves have not been shown thereon but such piping and valvesare shown diagrammatically in Fig. 12. Fluid pressure, for examplecompressed air at 200# per square inch, is supplied through a pipe I20to the inlet port valve III. Under suitable control of the correspondingplunger I01 the air so supplied to valve II I will at times be deliveredthrough a pipe or conduit I2I and flexible branches I22 to the clampingarm cylinders 4| and 42, thus to supply pressure fluid to the lower endsof said cylinders whereby to move the clamps I6 and I8 downwardly totheir clamping positions. On other occasions such air may be exhaustedfrom the cylinders 4| and 42 through an appropriate exhaust port I23.When the cycle commences that movement of the clamping members I6 and I8is the first that occurs and the clamping which is thus effected ismaintained until the splice has been completed. As a cushioning meansthe upper ends of the cylinders 4| and 42 are connected to alow-pressure fluidsupply line I24 which may carry, for example,compressed air at from 25 to 35# per square inch pressure. a

The valve 2 supplies pressure fluid through a conduit I25 to the airbags 90 and 9| within the clamping members I6 and I8. This pressurefluid may also be compressed air but preferably at selectively variablepressure to suit the particular splicing operations. Thispressure-supply line is indicated at I26 extending into valve II2.

Valve 4 receives fluid pressure, such as compressed air, atapproximately 150#. per square inch from a supply pipe I21 and itdistributes such fluid alternately to opposite ends of the knifecylinder 66 through conduits or pipes I28 and I29.

Valve II3 also receives pressure fluid from the line I21 and valve H4,and it distributes such pressure fluid to the lower end of the anvilcylinder 60 through conduits or pipes I30 and I3I which, incidentally,are also connected with safety valves I32 and the regulating check valveI 33. The valve II3 also supplies pressure fluid to the knife-stopcylinder 61 and to supplementary carriage-control cylinders 80 and 8|,such supply passing through pipes I35 and branch I 36, regulating checkvalves I31 and I38 as well as the three-way valve 16, pipe 11 andregulating check valve 18 previously mentioned.

The valve II also receives its supply of fluid from the tube I21 anddistributes it alternately to the opposite ends of the primarycarriage-control cylinder 56 through pipes I40 and MI and regulatingcheck valve I42.

The relative positions of the various pistons when the machine is atrest have already been described, and from such positions they are movedautomatically in proper sequence under the control of the unit 95.Variations in the cams may be made for specific adjustments of parts ofthe machine, and the total duration of the cycle may be varied bychanging the speed of the cam shaft 98. The cycle just referred toincludes all of the steps illustrated in Figs. 5 to 11 inclusive and itis to be understood that all of the machine parts at the end of thecycle come to rest in the same positions from which they started.

In operating the machine the attendant mere- 1y lays the intermediateportion T-3 of the unvulcanized inner tube or other stock over asuitable support I50, which is disposed above the clamping devices andthen places the ends T-I and T2 of such stock on top of the clampingmembers I5 and I1, leaving the extremities protruding therefrom.Thereafter the attendant grasps the switch handles |5I and I52(requiring both hands), and manipulates them to close switches I53 andI54, which switches are arranged in series with each other and supplyelectric current to operate the motor 96. As soon as the motor turnssufliciently to start the cam shaft 98 in its single revolution thecurrent is automatically by-passed around the switches I53 and I54 butin the meantime the clamping members I6 and I8 will have moved down intoclamping position and thereafter the operator or attendant will be in nodanger of being injured by the machine. If anything should go wrong heneeds merely to' kick inwardly a safety bar I55 which extendstransversely across the front of the base 64 adjacent to the floor lineand said safety bar, through its operative connections. will immediatelyinterrupt the cycle of operations'and return all of the machine parts totheir original positions of rest, except the anvil I8 which is lowered,and the carriages and H which are moved apart their full distance. The

operative connections of the safety bar I55 may be variously arrangedand modified as desired. In the illustrated embodiment, the bar I55 issupported by the lower ends of a pair of arms I10 which are pivoted at I1|, and which are connected by a link I12 to a lever I13 disposed withinthe base of the machine. The lever I13 is adapted to actuate a mastercontrol valve I14 to move the parts to their positions of rest as abovedescribed. It is to be understood that the bar I 55 and associated partsare not used in normal operation of the machine, but are provided onlyas a safety measure in the event that the operator should accidentallyor carelessly have his hands caught in the machine.

Preferably the knives 20 will be heated by an appropriate heatingelement I56 which is mounted between them upon the slide 62, suchheating elementbeing supplied with electric current and thermostaticallycontrolled at any desired temperature by a thermocouple I51 of anyordinary or preferred construction.

The abutment 1| may be adjusted by means of a hand wheel I60 whereby toset the machine for operation on stocks of different thickness andpreferably a gauge or indicating mechanism I6I is mounted in associationwith the adjusting mechanism for guidance of the attendant. A signallight I62 may be included in the operating circuit, it being soconnected that it will receive current and be lighted at the beginningof the cycle and will continue to be lighted until the very end of thecycle. This signal light does not in any way affect or modify theoperation of the machine, but is intended for the convenience of themachine attendant. A temperature control unit I58 is also preferablyused, such unit being commercially available in several difierent formsand being ordinarily mounted upon a wall or instrument panel at someconvenient location of the shop not necessarily immediately adjacent tothe machine. This temperature control unit as well as the powersupplying wires may be conveniently connected to a 'junction box I59located on or adjacent to the base of the machine.

From the foregoing description it will be evident that a novel methodhas been provided for splicing pieces of rubber together and moreparticularly for splicing inner-tube stock and tread stock inunvulcanized condition. Also novel mechanism has been provided forpracticing the method. The method is one which produces superior resultsand the apparatus is relatively simple, efficient and conducive toeconomy. Obviously numerous changes may be made in the steps of themethod and in the arrangement of parts of the apparatus and the right isherein reserved to make such changes as fall within the scope of theappended claims without departing from the spirit of the invention.

What We claim is:

1. A machine for splicing two portions of rubber comprisinglongitudinally movable carriages, means for clamping upon the carriagesthe rubber portions to be spliced, means for transversely cutting therubber so clamped, means for slightly moving the carriages apart duringthe cutting operation, and means for moving the carriages toward eachother at the end of the cutting operation to bring the cut rubbersurfaces into contact with each other.

2. A machine for splicing a plurality of pieces of unvulcanized rubberwhich comprises a pair of alined reciprocating carriages, means forclamping upon the carriages the pieces to be spliced, means for severingsmall portions from the ends of the clamped pieces with a combinedcutting and tearing action, and means for reciprocating the carriages tobring theexposed surfaces of the rubber into contact with each other.

3. A machine for splicing a plurality of pieces of unvulcanized rubberwhich comprises a pair of alined reciprocating carriages, means forclamping upon the carriages the pieces to be spliced, means for severingsmall portions from the ends of the clamped pieces with transverselyoff-set cuts, whereby said ends will be capable of meeting withouttrapping air between them, and means for reciprocating the carriages tobring the exposed surfaces of the rubber into complete contact with eachother.

4. A machine for splicing a plurality of pieces of unvulcanized rubberwhich comprises a pair of alined reciprocating carriages, means forclamping upon the carriages the pieces to be spliced, a reciprocatingknife for cutting portions'of rubber from the clamped piecesflmeans formoving the knife intermittently through the rubber, means for moving thecarriages apart during part of the movement of the knife, and

means for moving the carriages toward each other at the end of thecutting operation to bring the cut rubber surfaces into contact witheach other.

5. A machine for splicing an inner tube comprising clamping meansoperable to flatten and hold fiat the ends of the tube stock, means forsevering portions from said ends with off-set cuts whereby said endswill be capable of meeting without trapping air between them, and meansfor immediately thereafter bringing the so-cut ends into abuttingrelation to unite them permanently.

6. A machine for splicing an inner tube comprising clamping meansoperable to flatten and hold flat the ends of the tube stock, cuttingmeans I operable transversely through the clamped ends of the stock, andmeans for moving the clamping means and said clamped ends away from eachother during operation of said cutting,

prising clamping means operable to flatten and hold flat the ends of thetube stock, cutting means adapted to cut transversely. through theclamped ends of the stock, and means for moving both the clamping meansand the cutting means during at least part of the cutting operation. 1

9. A machine for splicing an inner tube comprising clamping meansoperable to flatten and hold flat the ends of the tube stock so thatopposing wall portions thereof have their inner surfaces in mutualcontact, cutting knives adapted to move transversely of the flattenedplane of the clamped ends, means for moving the knives in a straightline partly through one wall of the tube stock, means for moving theclamping means'apart during part of such movement

